[libcamera-devel] [PATCH v2] android: Rework request completion notification
Jacopo Mondi
jacopo at jmondi.org
Fri May 7 09:37:39 CEST 2021
Hi Hiro,
thanks for review
On Fri, May 07, 2021 at 12:50:13PM +0900, Hirokazu Honda wrote:
> Hi Jacopo, thank you for the patch.
>
> On Fri, May 7, 2021 at 12:00 AM Jacopo Mondi <jacopo at jmondi.org> wrote:
>
> > The current implementation of CameraDevice::requestComplete() which
> > handles event notification and calls the framework capture result
> > callback does not handle error notification precisely enough.
> >
> > In detail:
> > - Error notification is an asynchronous callback that has to be notified
> > to the framework as soon as an error condition is detected, and it
> > independent from the process_capture_result() callback
> >
> > - Error notification requires the HAL to report the precise error cause,
> > by specifying the correct CAMERA3_MSG_ERROR_* error code.
> >
> > The current implementation only notifies errors of type
> > CAMERA3_MSG_ERROR_REQUEST at the end of the procedure, before the
> > callback invocation.
> >
> > Rework the procedure to:
> >
> > - Notify CAMERA3_MSG_ERROR_DEVICE and close the camera in case a Fatal
> > error is detected (Fatal does not perform library teardown in
> > production builds)
> >
> > - Notify CAMERA3_MSG_ERROR_REQUEST if the libcamera::Request::status is
> > different than RequestCompleted and immediately call
> > process_capture_result() with all buffers in error state.
> >
> > - Notify the shutter event as soon as possible
> >
> > - Notify CAMERA3_MSG_ERROR_RESULT in case the metadata cannot be
> > generated correctly and call process_capture_result() with the right
> > buffer state regardless of metadata availability.
> >
> > - Notify CAMERA3_MSG_ERROR_BUFFER for buffers whose post-processing
> > failed
> >
> > While at it, return the CameraStream buffer by calling
> > cameraStream->putBuffer() regardless of the post-processing result.
> >
> > No regression detected when running CTS in LIMITED mode.
> >
> > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > ---
> >
> > v2:
> > - Rework a comment as suggested by Niklas
> > - As Niklas reported, dereferencing a unique_ptr<> which owns a nullptr has
> > an undefined behaviour. Replace that pattern by resetting the
> > resultMetadata
> > unique_ptr<> with a new one holding an empty CameraMetadata, as the
> > framework
> > requires on error.
> >
> > camera3.h:
> > * If there was an error producing the result metadata, result must be
> > an
> > * empty metadata buffer, and notify() must be called with
> > ERROR_RESULT.
> >
> >
> > std::unique_ptr<CameraMetadata> resultMetadata =
> > getResultMetadata(descriptor);
> > if (!resultMetadata) {
> > notifyError(descriptor.frameNumber_,
> > descriptor.buffers_[0].stream,
> > CAMERA3_MSG_ERROR_RESULT);
> >
> > /* The camera framework expects an empy metadata pack on
> > error. */
> > resultMetadata = std::make_unique<CameraMetadata>(0, 0);
> > }
> > captureResult.result = resultMetadata->get();
> >
> > ---
> > src/android/camera_device.cpp | 132 ++++++++++++++++++++--------------
> > src/android/camera_device.h | 3 +-
> > 2 files changed, 80 insertions(+), 55 deletions(-)
> >
> > diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> > index f1f26c775611..ea7ec8c05f88 100644
> > --- a/src/android/camera_device.cpp
> > +++ b/src/android/camera_device.cpp
> > @@ -2025,9 +2025,6 @@ int
> > CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
> >
> > void CameraDevice::requestComplete(Request *request)
> > {
> > - camera3_buffer_status status = CAMERA3_BUFFER_STATUS_OK;
> > - std::unique_ptr<CameraMetadata> resultMetadata;
> > -
> > decltype(descriptors_)::node_type node;
> > {
> > std::scoped_lock<std::mutex> lock(mutex_);
> > @@ -2035,7 +2032,8 @@ void CameraDevice::requestComplete(Request *request)
> > if (it == descriptors_.end()) {
> > LOG(HAL, Fatal)
> > << "Unknown request: " <<
> > request->cookie();
> > - status = CAMERA3_BUFFER_STATUS_ERROR;
> > + close();
> >
>
> close() calls Camera::stop(). Camera::stop() cancels the pending request
> and requestComplete() will be invoked. (this is not done so cf.
> https://patchwork.libcamera.org/project/libcamera/list/?series=1954)
> Furthermore, Camera::stop() is a blocking function. So I think calling
> close() here possibly causes the infinite-loop, e.g. when descriptors_ is
> somehow empty.
Mmm, you're right, it doesn't seem like an infinite loop but rather a
deadlock, as we're in critical section and all new requestComplete()
calls due to the Camera::stop() will contend this mutex
> Ah, but LOG(HAL, Fatal) causes the crash libcamera process, hmm..
I recall we had a compiler option to make Fatal not fatal (sorry...)
in production builds... I don't seem to be able to find it though.
If Fatal is always fatal, well, I can only notify the ERROR_DEVICE and
then crash, so no close is required.
If Fatal can actually be disabled I feel like close() will need to be
called according to the camera3 API, but I'm not sure if the framework
does that, or the HAL should do so, as I've found two contradictory
statements:
/**
* A serious failure occured. No further frames or buffer streams will
* be produced by the device. Device should be treated as closed. The
* client must reopen the device to use it again. The frame_number field
* is unused.
*/
CAMERA3_MSG_ERROR_DEVICE = 1,
This seems to imply the device should be re-opened and treated as
closed by the framwork, so the HAL has actually to close it.
* S6. Error management:
*
* Camera HAL device ops functions that have a return value will all return
* -ENODEV / NULL in case of a serious error. This means the device cannot
* continue operation, and must be closed by the framework. Once this error is
* returned by some method, or if notify() is called with ERROR_DEVICE, only
* the close() method can be called successfully. All other methods will return
* -ENODEV / NULL.
This seems to imply the framework calls close() after it receives
ERROR_DEVICE.
Could this maybe clarified with Ricky's team ?
>
>
>
> > + notifyError(0, nullptr, CAMERA3_MSG_ERROR_DEVICE);
> > return;
> > }
> >
> > @@ -2043,16 +2041,71 @@ void CameraDevice::requestComplete(Request
> > *request)
> > }
> > Camera3RequestDescriptor &descriptor = node.mapped();
> >
> > + /*
> > + * Prepare the capture result for the Android camera stack.
> > + *
> > + * The buffer status is set to OK and later changed to ERROR if
> > + * post-processing/compression fails.
> > + */
> > + camera3_capture_result_t captureResult = {};
> > + captureResult.frame_number = descriptor.frameNumber_;
> > + captureResult.num_output_buffers = descriptor.buffers_.size();
> > + for (camera3_stream_buffer_t &buffer : descriptor.buffers_) {
> > + buffer.acquire_fence = -1;
> > + buffer.release_fence = -1;
> > + buffer.status = CAMERA3_BUFFER_STATUS_OK;
> > + }
> > + captureResult.output_buffers = descriptor.buffers_.data();
> > + captureResult.partial_result = 1;
> > +
> > + /*
> > + * If the Request has failed, abort the request by notifying the
> > error
> > + * and complete the request with all buffers in error state.
> > + */
> > if (request->status() != Request::RequestComplete) {
> > - LOG(HAL, Error) << "Request not successfully completed: "
> > + LOG(HAL, Error) << "Request " << request->cookie()
> > + << " not successfully completed: "
> > << request->status();
> > - status = CAMERA3_BUFFER_STATUS_ERROR;
> > +
> > + notifyError(descriptor.frameNumber_,
> > + descriptor.buffers_[0].stream,
> > + CAMERA3_MSG_ERROR_REQUEST);
> > +
> > + for (camera3_stream_buffer_t &buffer : descriptor.buffers_)
> > + buffer.status = CAMERA3_BUFFER_STATUS_ERROR;
> > + callbacks_->process_capture_result(callbacks_,
> > &captureResult);
> > +
> > + return;
> > }
> >
> > + /*
> > + * Notify shutter as soon as we have verified we have a valid
> > request.
> > + *
> > + * \todo The shutter event notification should be sent to the
> > framework
> > + * as soon as possible, earlier than request completion time.
> > + */
> > + uint64_t sensorTimestamp =
> > static_cast<uint64_t>(request->metadata()
> > +
> > .get(controls::SensorTimestamp));
> > + notifyShutter(descriptor.frameNumber_, sensorTimestamp);
> > +
> > LOG(HAL, Debug) << "Request " << request->cookie() << " completed
> > with "
> > << descriptor.buffers_.size() << " streams";
> >
> > - resultMetadata = getResultMetadata(descriptor);
> > + /*
> > + * Generate the metadata associated with the captured buffers.
> > + *
> > + * Notify if the metadata generation has failed, but continue
> > processing
> > + * buffers and return an empty metadata pack.
> > + */
> > + std::unique_ptr<CameraMetadata> resultMetadata =
> > getResultMetadata(descriptor);
> > + if (!resultMetadata) {
> > + notifyError(descriptor.frameNumber_,
> > descriptor.buffers_[0].stream,
> > + CAMERA3_MSG_ERROR_RESULT);
> > +
> > + /* The camera framework expects an empy metadata pack on
> > error. */
> > + resultMetadata = std::make_unique<CameraMetadata>(0, 0);
> > + }
> > + captureResult.result = resultMetadata->get();
> >
> > /* Handle any JPEG compression. */
> > for (camera3_stream_buffer_t &buffer : descriptor.buffers_) {
> > @@ -2065,56 +2118,27 @@ void CameraDevice::requestComplete(Request
> > *request)
> > FrameBuffer *src =
> > request->findBuffer(cameraStream->stream());
> > if (!src) {
> > LOG(HAL, Error) << "Failed to find a source stream
> > buffer";
> > + buffer.status = CAMERA3_BUFFER_STATUS_ERROR;
> > + notifyError(descriptor.frameNumber_, buffer.stream,
> > + CAMERA3_MSG_ERROR_BUFFER);
> > continue;
> >
>
> Is this still continue? Perhaps return?
Is it ? my understandin is that if a single buffer fails, the request
can be completed and that single buffer state will be set to
CAMERA3_BUFFER_STATUS_ERROR and the framework has to be notified about
the CAMERA3_MSG_ERROR_BUFFER event. Metadata and other succesfully
completed buffers can be returned correctly if they have been properly
filled, hence I think we should continue and process the next
buffer...
A question: are there tests in the cros_camera_test package that
exercize these error paths ?
Thanks
j
>
>
> > }
> >
> > - int ret = cameraStream->process(*src,
> > - *buffer.buffer,
> > + int ret = cameraStream->process(*src, *buffer.buffer,
> > descriptor.settings_,
> > resultMetadata.get());
> > - if (ret) {
> > - status = CAMERA3_BUFFER_STATUS_ERROR;
> > - continue;
> > - }
> > -
> > /*
> > * Return the FrameBuffer to the CameraStream now that
> > we're
> > * done processing it.
> > */
> > if (cameraStream->type() == CameraStream::Type::Internal)
> > cameraStream->putBuffer(src);
> > - }
> >
> > - /* Prepare to call back the Android camera stack. */
> > - camera3_capture_result_t captureResult = {};
> > - captureResult.frame_number = descriptor.frameNumber_;
> > - captureResult.num_output_buffers = descriptor.buffers_.size();
> > - for (camera3_stream_buffer_t &buffer : descriptor.buffers_) {
> > - buffer.acquire_fence = -1;
> > - buffer.release_fence = -1;
> > - buffer.status = status;
> > - }
> > - captureResult.output_buffers = descriptor.buffers_.data();
> > -
> > - if (status == CAMERA3_BUFFER_STATUS_OK) {
> > - uint64_t timestamp =
> > - static_cast<uint64_t>(request->metadata()
> > -
> > .get(controls::SensorTimestamp));
> > - notifyShutter(descriptor.frameNumber_, timestamp);
> > -
> > - captureResult.partial_result = 1;
> > - captureResult.result = resultMetadata->get();
> > - }
> > -
> > - if (status == CAMERA3_BUFFER_STATUS_ERROR ||
> > !captureResult.result) {
> > - /* \todo Improve error handling. In case we notify an error
> > - * because the metadata generation fails, a shutter event
> > has
> > - * already been notified for this frame number before the
> > error
> > - * is here signalled. Make sure the error path plays well
> > with
> > - * the camera stack state machine.
> > - */
> > - notifyError(descriptor.frameNumber_,
> > - descriptor.buffers_[0].stream);
> > + if (ret) {
> > + buffer.status = CAMERA3_BUFFER_STATUS_ERROR;
> > + notifyError(descriptor.frameNumber_, buffer.stream,
> > + CAMERA3_MSG_ERROR_BUFFER);
> >
>
> same here.
>
> -Hiro
>
> + }
> > }
> >
> > callbacks_->process_capture_result(callbacks_, &captureResult);
> > @@ -2136,23 +2160,23 @@ void CameraDevice::notifyShutter(uint32_t
> > frameNumber, uint64_t timestamp)
> > callbacks_->notify(callbacks_, ¬ify);
> > }
> >
> > -void CameraDevice::notifyError(uint32_t frameNumber, camera3_stream_t
> > *stream)
> > +void CameraDevice::notifyError(uint32_t frameNumber, camera3_stream_t
> > *stream,
> > + camera3_error_msg_code code)
> > {
> > camera3_notify_msg_t notify = {};
> >
> > - /*
> > - * \todo Report and identify the stream number or configuration to
> > - * clarify the stream that failed.
> > - */
> > - LOG(HAL, Error) << "Error occurred on frame " << frameNumber << "
> > ("
> > - << toPixelFormat(stream->format).toString() << ")";
> > -
> > notify.type = CAMERA3_MSG_ERROR;
> > notify.message.error.error_stream = stream;
> > notify.message.error.frame_number = frameNumber;
> > - notify.message.error.error_code = CAMERA3_MSG_ERROR_REQUEST;
> > + notify.message.error.error_code = code;
> >
> > callbacks_->notify(callbacks_, ¬ify);
> > +
> > + if (stream)
> > + LOG(HAL, Error) << "Error occurred on frame " <<
> > frameNumber << " ("
> > + <<
> > toPixelFormat(stream->format).toString() << ")";
> > + else
> > + LOG(HAL, Error) << "Fatal error occurred on device";
> > }
> >
> > /*
> > diff --git a/src/android/camera_device.h b/src/android/camera_device.h
> > index 23457e47767a..8d5da8bc59e1 100644
> > --- a/src/android/camera_device.h
> > +++ b/src/android/camera_device.h
> > @@ -101,7 +101,8 @@ private:
> > std::tuple<uint32_t, uint32_t> calculateStaticMetadataSize();
> > libcamera::FrameBuffer *createFrameBuffer(const buffer_handle_t
> > camera3buffer);
> > void notifyShutter(uint32_t frameNumber, uint64_t timestamp);
> > - void notifyError(uint32_t frameNumber, camera3_stream_t *stream);
> > + void notifyError(uint32_t frameNumber, camera3_stream_t *stream,
> > + camera3_error_msg_code code);
> > std::unique_ptr<CameraMetadata> requestTemplatePreview();
> > std::unique_ptr<CameraMetadata> requestTemplateVideo();
> > libcamera::PixelFormat toPixelFormat(int format) const;
> > --
> > 2.31.1
> >
> > _______________________________________________
> > libcamera-devel mailing list
> > libcamera-devel at lists.libcamera.org
> > https://lists.libcamera.org/listinfo/libcamera-devel
> >
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